PY3 is a synthetic organic pigment in the Arylide family. As a commonly used lemon yellow pigment, it performs the function of a green bias yellow on many artists' palettes. It doesn't look particularly greenish in masstone, but is instead a very high chroma bright yellow. This allows it to create the most vivid greens when mixed with equally high chroma blue or green pigments like cobalt teal or especially the phthalocyanines. The resulting greens can appear almost fluorescent. It could be argued that this pigment is closer to a true mixing primary yellow, especially in the Magenta/Cyan/Yellow system, as it can also create some very bright oranges. However, these lack some of the warmth obtained with PY74, which is more of a middle yellow.
It is one of the more naturally transparent pigments in pure masstone, however white can be added to impart opacity and PY3 retains its vibrancy surprisingly well before, eventually appearing pastel or overly pale.
Usage tip.
PY3 can retain good vibrancy when tinted with white, possibly due to its already light value, however it can quickly be overpowered by darker colours. Thus, when using PY3 to mix colours, it is advisable to start with PY3 and add other colours in small increments until the desired colour is reached.